[This post was originally published on The Secular Outpost on November 25, 2006 and then republished on February 11, 2016. It was republished here on November 7, 2021 with the date manually adjusted to reflect its original publication date. The link was also updated to its current location.]
There are a variety of approaches to formulating an argument from evil against theism. Two of the most influential versions of the evidential argument from evil were developed by atheist William Rowe and agnostic Paul Draper. Both involve appeals to pain. In a recent entry on his blog, Victor Reppert tries to turn the tables on proponents of arguments from evil (pain) by arguing that pain is a problem for atheists. Reppert formulates his argument against naturalism as follows.
1. If naturalism is true, then consciousness does not emerge.
2. If consciousness does not emerge, then pain does not exist.
3. Therefore, if naturalism is true, then pain does not exist.
4. Pain exists.
5. Therefore, naturalism is false.
Notice that premise (1) of the above argument entails that naturalism and consciousness are logically incompatible. Reppert's argument may be reasonably characterized, then, as a very specific example of a logical argument from consciousness against naturalism (as opposed to an evidential argument from consciousness as defended by Richard Swinburne). I believe this characterization is further supported by Reppert's statement, "the actual internally experienced state of pain is a huge, hard problem for atheistic naturalism, a problem that I personally consider to be logically impossible to solve."
Does Reppert literally mean what he says? As a so-called logical argument against naturalism, it isn't clear to me why this argument is in any way an improvement over logical arguments from evil against theism. In particular, Reppert has not yet presented a defense of (1) in its current form (i.e., lacking some sort of probabilistic hedge).
Perhaps, however, Reppert did not intend for his argument to be worded so strongly. Instead, he might say, we should understand his argument as an evidential argument against naturalism. If so, it seems to me that Reppert's argument from pain violates the Rule of Total Evidence. Allow me to explain. Let us assume, for the sake of argument that Reppert is correct that consciousness is antecedently more likely on theism than on naturalism. Furthermore, as Reppert points out, pain presupposes consciousness. It doesn't follow from these two assumptions, however, that the statement, "The kinds and distribution of pain we find in the world is epistemically more probable on naturalism than on theism," is false.
Here's why. Reppert has committed the fallacy of understated evidence. In general terms, we could say that Reppert has identified some general fact F (consciousness exists) about a topic X (consciousness) that is antecedently more likely on theism than on naturalism. It could still be the case that a more specific fact (S) about X is antecedently more likely on naturalism than on theism. As Paul Draper writes, "we know a lot more about phenomenal consciousness than just that it exists" ("Partisanship and Inquiry in the Philosophy of Religion," unpublished paper). Draper then gives an example of a more specific fact about consciousness, a fact that, given consciousness exists, is more probable on naturalism than on theism. As Draper explains, we also know from neuroscience that the mind is dependent upon the physical brain, a fact that is more likely on naturalism and consciousness than on theism and consciousness. Thus, as Draper concludes, "when the available evidence about consciousness is fully stated, it is far from clear that it significantly favors theism."
